Sutherlandia frutescens (balloon pea)

Balloon pea occurs naturally throughout the dry parts of Southern Africa, in the Western Cape and up the west coast as far north as Namibia and into southwest Botswana, and in the western Karoo to Eastern Cape, Northern Cape, Free State, KwaZulu-Natal and Lesotho. Occurrences further north and east in South Africa may be introduced.

Fruits of Sutherlandia frutescens (Image: Wolfgang Stuppy)

Sutherlandia frutescens is a lax spreading shrub to 1.2 m high, with prostrate to erect stems. The leaves are 3-10 cm long, and are pinnate with oblong to linear-elliptic leaflets, which are mostly three or more times longer than wide, and slightly to densely hairy. The leaves are greyish-green to silvery in appearance. The bright orange-red to scarlet flowers are borne in terminal racemes, each of 3-6 flowers. Flowering occurs from July to December. The fruit is a balloon-like, inflated membranous pod, 1.3-2 times as long as wide, bearing a persistent upturned style. The seeds are black, flattened, and about 3 mm in diameter.

There are a number of closely related species, for example S. microphylla and S. montana, but they are difficult to distinguish from S. frutescens because they often grade into each other. Some botanists consider them to be merely different forms of a single large and variable species. Currently six species are recognised in the genus, all from Southern Africa.

Kew's Millennium Seed Bank partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

Description of seeds: Average 1,000 seed weight = 8.7 g.
Number of seed collections stored in the Millennium Seed Bank: 9.
Seed storage behaviour: Orthodox (the seeds of this plant survive being dried without significantly reducing their viability, and are therefore amenable to long-term frozen storage such as at the MSB).
Germination testing: 100% germination [pre-sowing treatments = seed scarified (chipped with scalpel); germination medium = 1% agar; germination conditions = 21°C, 12/12].
Composition values: Average oil content = 2.8%. Average protein content = 29.2%.

Sutherlandia frutescens, Northern Cape Province, South Africa (Image: Brain Schrire)

Balloon pea pods and stems are held in the behind-the-scenes Economic Botany Collection.

A Medley of Flowers from Table Mountain, Cape of Good Hope by Marianne North (Image: RBG Kew)

Marianne North Gallery - A Medley of Flowers from Table Mountain, Cape of Good Hope

Flora Zambesiaca - Sutherlandia frutescens

Information and links on Sutherlandia frutescens

Sutherlandia and cancer

Medicinal plant 'fights' AIDS (BBC News article)

A safety study of Sutherlandia frutescens

PlantZAfrica - Sutherlandia frutescens

Aluka - Sutherlandia frutescens